Hetzner Networks

Hi,
I plan to use Hetzner's external firewall. Optionally with a network.
Anything to keep in mind?
Or tips and experiences?

I would be very grateful to you.

Works good. Use groups.

Like when working with Firewalls for any enhance system

Whitelist the IP's of each of the other Enhance servers
Whitelist any static IP of your office or VPN
Consider what ports you want open on each server (if you don't use FTP, don't expose it)
Be sure to consider both ipv4 and ipv6 in your firewall rules

If you plan to send emails, be sure to enable port 25 for both outgoing and incoming

Lastly

Always validate your firewall rules, you can download nmap and run it from your own computer or use online port scanning tools.